1. Field of the Invention
The invention relates in general to a method of fabricating a bubble-type micro-pump, and more particularly to a method of fabricating an electrolysis bubble-type micro-pump applied to a microfluidic chip.
2. Description of the Related Art
As the technology continues to evolve, the application of microfluidic chip is brought out in recent years. Generally speaking, a microfluidic chip roughly includes a fluidic channel and a fluid-dynamic mechanism. The design of micro-pump especially plays an important role in the movement of the fluid.
The detailed design, operating principle and various application fields can be found in many research documents and journals. For example, in “droplet movement on horizontal surface with gradient surface energy” disclosed in Science in China, volume 37, page 402-408 (2007), dodecyltrichlorosilane is used on silicon substrate to form a surface with gradient surface energy by chemical vapor deposition. The U.S. Pat. No. 6,231,948 reveals a pervious web to rapidly transport fluid away from the contacting surface toward another surface. The U.S. Pat. No. 6,232,521 reveals a low surface energy material applied to a back sheet of sanitary napkin to form a hydrophobic gradient between the back sheet and the core, which reduces leakage. A similar U.S. Pat. No. 5,658,639, reveals a non-woven web having the opposite first and the second surfaces. Several channels are used for transporting liquid. When liquid contacts the first surface with lower surface energy, the surface energy gradient drives the liquid to flow toward the second surface. Therefore, the web is suited for use as a top sheet of a sanitary napkin. Furthermore, the U.S. Pat. No. 5,792,404 reveals a method for forming surface energy gradients. Several three-dimensional raised rib-like portions are produced to increase the caliper of the non-woven web, so that fluid can flow away from the wearer-contacting surface and into the absorbent structure.
The design of micro-pump can be divided into two types according to the driving principle of the fluid. One is to drive fluid through mechanical method, such as bubble pump, membrane pump, diffuser pump, etc. These pumps use the mechanical elements to drive fluid. The other one is to drive fluid through induced electric field, such as electro-osmotic pump, electrophoretic pump, electro-wetting pump, etc. Fixed electrodes are formed in these pumps, and electric field is generated to drive fluid after voltage is applied.
It is an object to overcome the limitations of the process and to fabricate a microfluidic chip, such as a micro-pump, with precision structure and high-precision flow-rate control while controlling the manufacture cost to meet the demand of mass production.